A lunar eclipse occurs when the Earth's shadow falls on the moon. Lunar eclipses occur, on average, about every 6 months.

月食的发生，是由于地球的影子落在月球上。月食发生的频率平均是6个月一次。

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A lunar eclipse occurs when the Earth's shadow falls on the moon.

月食的发生，是由于地球的影子落在月球上。

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During the eclipse, the best viewing in North America found the coppery lunar disc high in a cold winter sky, the Moon reddened by light filtering into the Earth's dark central shadow or umbra.

在这次月食中，在北美洲最佳观测点可以看到在寒冬的天空中出现一轮铜黄色的月盘，这是因为月亮由于地球黯淡阴影的中心滤过的光芒而变红了。

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This was when it was first pointed out that, because sunlight near the lunar poles comes in at a shallow angle, the floors of the deeper craters there might be in permanent shadow.

ECONOMIST: Creative destruction